1. Field of the Invention
The present invention relates to an air cleaner for an engine mainly mounted on a straddle-type vehicle such as a straddle-type four-wheel vehicle or a motorcycle.
2. Description of the Related Art
FIG. 10 shows a known air cleaner 100 mounted on a vehicle such as a straddle-type four-wheel vehicle (JP-A 2003-286916). The air cleaner 100 has a cleaner case 101 formed by joining together an upper case member 102 and a lower case member 103. The cleaner case 101 contains a filter assembly 105 therein. A cleaner inlet (air intake port) 110 is formed on the side wall of the lower case member 103. A cleaner outlet (air outlet port) 111 to be connected to a carburetor is formed on the bottom wall of the lower case member 103. Air (the open air) is taken through the air intake port 110 to an inside of the cleaner case 101. The induced air passes through the filter assembly 105 from the outside to the inside so as to be filtered. The filtered air is supplied to the carburetor through the air outlet port 111 on the bottom.
FIG. 11 shows an exploded perspective view of the filter assembly 105 of FIG. 10. The filter assembly 105 includes a lower holder 120 which is made of resin, an upper holder 121 which is made of metal, a top cover 122 which is made of metal, and a cylindrical cleaner element 123 which is made of urethane foam.
The lower holder 120 includes an annular base 131, a plurality of upright support pillars 132 which are integrally formed with the base 131. The base 131 is fastened to the lower case member 103 by bolts 135. Female screw holes 137 are formed on the upper ends of the support pillars 132. The top cover 122 is formed integrally with the upper holder 121 with metal and has bolt through holes 138.
The upper holder 121 is formed in a cylindrical shape corresponding to the cylindrical shape of the cleaner element 123 and has many holes 140 which are made by punching. A wire gauze 141 as a flame arrester is integrally attached to the inner surface of the upper holder 121.
The cleaner element 123 is disposed on the outer surface of the upper holder 121. The upper holder 121 is disposed around the support pillars 132 of the lower holder 120 and is fastened to the upper end of the lower holder 120 with bolts 143. Thereby, the cleaner element 123 is held between the lower surface of the top cover 122 and the upper surface of the base 131.
When the cleaner element 123 is replaced, first, the upper case member 102 is removed. Next, the bolts 143 shown in FIG. 11 are removed, and the upper holder 121 with the top cover 122 and the cleaner element 123 are removed all together. Then, a new cleaner element 123 is disposed on the upper holder 121, and the upper holder 121 with the cleaner element 123 is mounted on the lower holder 120 together with the top cover 122.
As shown in FIG. 11, the top cover 122 of metal, the upper holder 121 of metal, and the wire gauze 141 are formed as an integral unit. Therefore, the manufacturing cost thereof increases due the increased number of assembling steps, and the weight thereof also increases. Moreover, a replacement of the cleaner element 123 requires much work since the integral metal unit including the three members 121, 122, 141 should be removed in order to replace the cleaner element 123.